<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .div{
            background-color: #ccc;
            
            width: 200px;
            height:100px;
            /* 内边距 */
            /* padding: 10px 20px 30px 50px; */
            padding: 10px 20px 30px;
            /* padding: 25px 50px; */
            /* padding: 50px; */
            /* 边框 */
            /* border: 10px solid red; */
            border-bottom: 10px solid red;
            border-top: 10px solid red;
            border-left: 10px solid red;
            /* 外边距 */
            margin: 100px;
        }
    </style>
</head>
<body>
    <h1>盒子模型</h1>
    <sapn class="div">
        盒子
    </span>
</body>
</html>